Luxi Light Meter Adapter for iPhone 5/5s Review


The humble incident light meter is one of the small casualties of the digital revolution. What was once an indispensable piece of equipment for any serious photographer has now been mostly forgotten by most holding a camera today. Why bother to meter when you can just take one—or one hundred—test shots with your DSLR and look at the LCD? Plus, when you are shooting RAW, you can just fix exposure later, dude!

There is still a place in your camera bag for a light meter
That having been said, for the smart photographer, there is still a place for the light meter in today’s world. After all, no matter how fancy, in-camera meters still are just measuring reflective light. While there is a world of difference between the in-camera light meters today and those of the cameras of yesteryear, there are still many situations where they can be fooled. This is why you still see a handheld incident light meter show up on many pro shooter’s “what’s in the bag” lists. These shooters know that a quick light reading can save the day and capture the moment exactly in the way they envision it.

I tend to find myself in that camp. I think a light meter is a very handy thing to have. While I admit to using it less than I once did, my trusty Sekonic L328 has traveled the world with me. It’s had a long life, but has provided accurate exposure readings in every situation I’ve been in. You can still find them, used, in the $125 range. Or you can spend $200-400 and pick up a current production Sekonic like the L758 or L308S.


Or, you can spend $30 at and pick up the Luxi Light Meter Adapter for your iphone 4/4s/5/5s. Created out of a wildly successful Kickstarter campaign (the goal was $10,000, they raised $120,000), the Luxi is a small plastic diffusion dome that fits over your iPhone’s front-facing camera. It comes with a small lanyard (that I mostly felt was in the way) and a soft pouch for storage (that I found very handy, as the Luxi mostly lived in the bottom of my camera bag). The Luxi slides onto the top edge of your iPhone, in the same way that other iPhone accessories such as the Olloclip lens do. Like most all of these slide on accessories, the Luxi is simply held on by the friction between it and the phone. There is a springy sort of “leaf” on the back that helps increase that friction, and overall it does a good job staying on there. But it bears in mind that you can easily “scrape” the Luxi off if you aren’t careful. The Luxi’s ABS plastic construction seems solid, and it is light weight, yet I would not like to see the results of it being dropped too many times onto hard or rough surfaces.

How well does it perform? 
Well, first things first, the Luxi doesn’t come with a light metering app. Extrasensory Devices, the company behind the Luxi, claims they will have their own app out soon. But until then, you will have to head down to the app store and pick one of the existing ones. Thankfully, there are a number of free/cheap apps to choose from. I used the thrillingly named (but free) “Pocket Light Meter” app from Nuwaste studios. It has a “Luxi” incident mode specifically designed for using with the Luxi. In all honesty, I thought the Luxi worked quite well. Compared to my L328, I found the Luxi to underexpose by about a stop. However, it did this fairly consistently. So once I used Pocket Light Meter’s calibration option to dial in a stop of correction, the exposures matched up pretty well.

However, it is worth noting that there is a limit to the accuracy of this sort of design. It is a passive adapter that is limited by the sensitivity of the camera in your phone and the app that is being used. This is going to be particularly notable in very low light situations. Thus, one would guess that the iPhone 5S camera would provide better results than previous models. Still, the Luxi does an impressive job at its price point. I think my only major gripe with it is the fact that I have not seen any light meter app that would let you do flash metering. This really isn’t the fault of the Luxi itself and is something that can probably be fixed in a future app. I hope Extrasensory Devices is keeping that in mind as a function for its own app.

The Luxi small, light, cheap, and more accurate than I would have expected. I’d say it is well worth $30, especially for someone who doesn’t already have a light meter.

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    • Sounds interesting but not confidence building that there is a stop difference between your Sekonic and the app.


      It's also extremely unlikely that flash metering can ever be offered by a software app alone. The flash duration is simply too short for the phone's camera to be able to sense the light.

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    • I'm intrigued. I use the Pocket Light Meter app (without a dome) on occasion, and find that it's surprisingly useful. The dome would help. But alas, I keep my iPhone 5 in a rubbery Otterbox housing (since I'm very mean to my phone). It would be interesting to see a solution that can deal with the fatter configuration of a clad phone.

      I've been ramping up for drone-based aerial photography lately, and have moved my Sekonic meter from my camera bag over to the Peli case that has the drone's RF gear in it. Why? Because I'm having to make exposure decisions on the ground, and send the camera up in manual mode (unless I want to trust auto-ISO, which isn't always a bad thing). But because I've always got the iPhone in my pocket when I'm out shooting, it would be nice to have one less device rattling around, needing batteries, and the like - even if I have to adjust by a stop to get it right. But: not working on a clad phone is sort of a deal breaker. Any thoughts on that, Josh? 

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    • Might check out which is another kickstarter thing. It uses the plug instead of covering the camera, although it's quite a bit more expensive.
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